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Re: [IRCA] Updated frequency offset for Tonga?
- Subject: Re: [IRCA] Updated frequency offset for Tonga?
- From: Nick Hall-Patch <nhp@xxxxxxxx>
- Date: Thu, 01 Aug 2013 02:29:58 +0000
I'll have to look again as to the reasoning for using higher
frequencies for a reference. I thought that with the SDRs, it no
longer made much of a difference, i.e. that an error of 1 Hertz at,
say 21MHz, was the same as an error of 1 Hertz at 1MHz.
I'm sure that folks who have been paying better attention than I will
put me right!
And, I do try for better accuracy than 1 Hertz myself. Darned
technology is making too many DX stations too close to the exact
frequency, so there is nothing unique about their signature.
best wishes,
Nick
At 13:21 31-07-13, you wrote:
I have the same experience during 10-15 years of using WWV/WWVH
carrier as reference here in Finland: the shift caused by Doppler
shift or spread by propagation is exaggerated. I often see it spread
a bit, but it looks like being symmetrical, so there isn't any
problem to see the centre anyway. Sometimes it can be one-sided and
then I have noticed the centre being off by 1 Hz. But even if it
were off by 2 Hz which I haven't noticed, it still makes an error of
only 0.2 Hz at 1500 kHz, which is far better than using anything of
MW as reference.
73, Mauno
29.7.2013 8:59, Nick Hall-Patch kirjoitti:
That's really intriguing Chuck. Thanks for pointing that article out.
I wonder what causes the spread in the audio spectra that I often
see when I get, say, a 400Hz beat to WWV at night? (compared to
the more solid single frequency beat note that I usually see with
something like KSL) This happens with my NetSDR and R8 so doesn't
seem related to the radio used. The shifts may well average out to
a single beat note, but it's pretty ugly on a second by second basis.
I'll have to find out where got the suggestion of using WWVB as a
reference rather than the higher frequency standard stations, due
to propagation anomalies.
best wishes,
Nick
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